binder: Change from C11 <stdatomic.h> to C++11 <atomic>.

Change-Id: Ib831a9ccfcc7089940d37883d860574359c270e2
diff --git a/include/binder/Binder.h b/include/binder/Binder.h
index 86628a0..f849fd4 100644
--- a/include/binder/Binder.h
+++ b/include/binder/Binder.h
@@ -17,7 +17,7 @@
 #ifndef ANDROID_BINDER_H
 #define ANDROID_BINDER_H
 
-#include <stdatomic.h>
+#include <atomic>
 #include <stdint.h>
 #include <binder/IBinder.h>
 
@@ -71,7 +71,7 @@
 
     class Extras;
 
-    atomic_uintptr_t    mExtras;  // should be atomic<Extras *>
+    std::atomic<Extras*> mExtras;
             void*       mReserved0;
 };
 
@@ -95,7 +95,7 @@
 
     IBinder* const          mRemote;
     RefBase::weakref_type*  mRefs;
-    volatile int32_t        mState;
+    std::atomic<int32_t>    mState;
 };
 
 }; // namespace android